JP2018207034A - Wafer generation device - Google Patents

Abstract

To provide a wafer generation device capable of generating a wafer automatically from an ingot.SOLUTION: A wafer generation device 2 comprises holding means 4 for holding an ingot 150, flattening means 6 for flattening a top face of the ingot 150 held by the holding means 4 by grinding, laser irradiation means 8 for forming an exfoliation layer 170 by irradiating the ingot 150 with a laser light beam LB while positioning a focusing point FP of the laser light beam LB of such a wavelength as having permeability for the ingot 150 at a depth corresponding to a thickness of the wafer to be generated from the top face of the ingot 150 held by the holding means 4, wafer peeling means 10 for holding the top face of the ingot 150 and peeling the wafer 172 from the exfoliation layer 170, and wafer housing means 12 for housing the peeled wafer 172.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wafer generating apparatus that generates a wafer from an ingot.

Devices such as ICs, LSIs, and LEDs are formed by stacking functional layers on the surface of a wafer made of Si (silicon), Al ₂ O ₃ (sapphire), or the like, and partitioning them by scheduled division lines. Moreover, a power device, LED, etc. are formed by laminating a functional layer on the surface of a wafer made of single crystal SiC (silicon carbide) and dividing it by a division line. The wafer on which the device is formed is processed into a division line by a cutting device or a laser processing device and divided into individual devices, and each divided device is used for an electric device such as a mobile phone or a personal computer.

  The wafer on which the device is formed is generally produced by thinly cutting a cylindrical ingot with a wire saw. The front and back surfaces of the cut wafer are polished into a mirror surface (see, for example, Patent Document 1). However, when the ingot is cut with a wire saw and the front and back surfaces of the cut wafer are polished, a large portion (70 to 80%) of the ingot is discarded, which is uneconomical. In particular, in a single crystal SiC ingot, the hardness is high and it is difficult to cut with a wire saw, and it takes a considerable amount of time, so the productivity is poor, and there is a problem in efficiently generating a wafer with a high unit cost of the ingot. Yes.

  Therefore, the condensing point of the laser beam having a wavelength transmissive to the single crystal SiC is positioned inside the single crystal SiC ingot, and the single crystal SiC ingot is irradiated with the laser beam to form a release layer on the planned cutting surface. There has been proposed a technique for peeling a wafer from a single crystal SiC ingot along a planned cutting surface on which a layer is formed (see, for example, Patent Document 2).

JP 2000-94221 A JP 2013-49161 A

  However, the step of forming a release layer on the ingot, the step of peeling the wafer from the ingot, and the step of grinding and flattening the upper surface of the ingot are performed manually, and there is a problem that the production efficiency is poor.

  An object of the present invention made in view of the above-mentioned fact is to provide a wafer generating apparatus capable of automatically generating a wafer from an ingot.

  In order to solve the above problems, the present invention provides the following wafer generating apparatus. That is, a wafer generating apparatus for generating a wafer from an ingot, the holding means for holding the ingot, the flattening means for grinding and flattening the upper surface of the ingot held by the holding means, and the holding means Laser irradiation means for locating a condensing point of a laser beam having a wavelength transmissive to the ingot at a depth corresponding to the thickness of the wafer to be generated from the upper surface of the formed ingot and irradiating the ingot with the laser beam to form a release layer And a wafer generating device comprising at least a wafer peeling means for holding the upper surface of the ingot and peeling the wafer from the peeling layer, and a wafer containing means for containing the peeled wafer.

  Preferably, an ingot accommodating means for accommodating the ingot and an ingot conveying means for conveying the ingot from the ingot accommodating means to the holding means are included. It is preferable to include cleaning means for cleaning the ingot flattened by the flattening means. The holding means is disposed on a turntable, and the holding means is conveniently positioned at least on the flattening means, the laser irradiation means, and the wafer peeling means by rotation of the turntable.

  The wafer generator provided by the present invention includes a holding means for holding an ingot, a flattening means for grinding and flattening an upper surface of the ingot held by the holding means, and an upper surface of the ingot held by the holding means. A laser irradiation means for locating a condensing point of a laser beam having a wavelength transmissive to the ingot at a depth corresponding to the thickness of the wafer to be generated from the laser, and irradiating the laser beam on the ingot to form a release layer; and an upper surface of the ingot A wafer peeling means for holding the wafer from the peeling layer and a wafer containing means for containing the peeled wafer, so that the wafer is automatically generated from the ingot and accommodated in the wafer containing means. Thus improving production efficiency.

1 is a perspective view of a wafer generator configured in accordance with the present invention. The principal part perspective view of the wafer production | generation apparatus shown in FIG. The principal part expansion perspective view of the planarization means shown in FIG. The schematic diagram which shows the state from which the wash water is injecting from the 1st washing | cleaning part of a washing | cleaning means, and the compressed air is injecting from the 2nd washing | cleaning part. The perspective view of the laser irradiation means shown in FIG. The perspective view of the laser irradiation means shown by omitting the frame from the laser irradiation means shown in FIG. The block diagram of the laser irradiation means shown in FIG. The perspective view of the wafer peeling means shown in FIG. Sectional drawing of the wafer peeling means shown in FIG. The perspective view of the ingot conveyance means shown in FIG. (A) Front view of ingot, (b) Plan view of ingot. (A) The perspective view of an ingot and a substrate, (b) The perspective view which shows the state by which the substrate was mounted | worn with the ingot. The perspective view which shows the state in which the holding process is implemented. The top view which shows the state in which the 1st ingot was positioned in the flattening position, and the 2nd ingot was positioned in the stand-by position. The top view which shows the state in which the 1st ingot was positioned in the peeling layer formation position, the 2nd ingot was positioned in the planarization position, and the 3rd ingot was positioned in the standby position. (A) The perspective view which shows the state in which the peeling layer formation process is implemented, (b) The front view which shows the state in which the peeling layer formation process is implemented. (A) The top view of the single crystal SiC ingot in which the peeling layer was formed, (b) BB sectional drawing in (a). The first ingot is positioned at the wafer peeling position, the second ingot is positioned at the peeling layer forming position, the third ingot is positioned at the flattening position, and the fourth ingot is positioned at the standby position. The top view which shows a state. (A) The perspective view which shows the state in which the liquid tank body is located above a chuck table, (b) The perspective view which shows the state in which the lower surface of the liquid tank body contacted the upper surface of the chuck table. The perspective view which shows the state from which the wafer was peeled from the ingot by the wafer peeling means. The first ingot is positioned at the standby position, the second ingot is positioned at the wafer peeling position, the third ingot is positioned at the peeling layer forming position, and the fourth ingot is positioned at the flattening position. The top view which shows a state. The first ingot is positioned at the flattening position, the second ingot is positioned at the standby position, the third ingot is positioned at the wafer peeling position, and the fourth ingot is positioned at the peeling layer forming position. The top view which shows a state. The first ingot is positioned at the release layer forming position, the second ingot is positioned at the flattening position, the third ingot is positioned at the standby position, and the fourth ingot is positioned at the wafer peeling position. The top view which shows a state.

  Hereinafter, embodiments of a wafer generating apparatus configured according to the present invention will be described with reference to the drawings.

  The wafer generator 2 shown in FIG. 1 includes a holding unit 4 that holds an ingot, a flattening unit 6 that grinds and flattens an upper surface of the ingot held by the holding unit 4, and an ingot held by the holding unit 4. A laser irradiating means 8 for locating a condensing point of a laser beam having a wavelength transparent to the ingot at a depth corresponding to the thickness of the wafer to be generated from the upper surface of the substrate and irradiating the ingot with the laser beam to form a release layer; It is comprised at least from the wafer peeling means 10 which hold | maintains the upper surface of an ingot, and peels a wafer from a peeling layer, and the wafer accommodating means 12 which accommodates the peeled wafer.

  The holding means 4 will be described with reference to FIG. The base 14 of the wafer generator 2 is formed with a rectangular turntable storage 16 that is recessed downward from the upper surface of the base 14. A circular turntable 18 is rotatable in the turntable storage 16. Contained. The turntable 18 is rotated about an axis extending in the Z-axis direction through the radial center of the turntable 18 by a turntable motor (not shown) built in the base 14. The holding means 4 in the illustrated embodiment includes four circular chuck tables 20 that are rotatably disposed on the upper surface of the turntable 18. Each chuck table 20 is conveniently positioned at least on the flattening means 6, the laser irradiation means 8, and the wafer peeling means 10 by the rotation of the turntable 18. In the illustrated embodiment, as shown in FIG. 2, each chuck table 20 is formed with a standby position P <b> 1, a flattening position P <b> 2 below the flattening means 6, and a peeling layer formation below the laser irradiation means 8 by the rotation of the turntable 18. It is positioned at a position P3, a wafer peeling position P4 below the wafer peeling means 10. Each chuck table 20 is rotated around an axis extending in the Z-axis direction through the radial center of each chuck table 20 by four chuck table motors (not shown) built in the base 14. It is rotated. The four chuck tables 20 arranged at equal intervals in the circumferential direction of the turntable 18 (with an interval of 90 degrees) are partitioned by a cross-shaped partition wall 18 a disposed on the upper surface of the turntable 18. ing. A circular suction chuck 22 made of a porous material and extending substantially horizontally is disposed on the upper surface of each chuck table 20, and each suction chuck 22 is a suction means (not shown) by a flow path. )It is connected to the. Each chuck table 20 constituting the holding unit 4 can suck and hold the ingot placed on the upper surface of the suction chuck 22 by generating a suction force on the upper surface of the suction chuck 22 by the suction unit. . The Z-axis direction is the vertical direction indicated by the arrow Z in FIG. 2 is a direction orthogonal to the Z-axis direction, and a Y-axis direction indicated by an arrow Y in FIG. 2 is a direction orthogonal to the X-axis direction and the Z-axis direction. The plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

  As shown in FIG. 2, the flattening means 6 is mounted on a mounting wall 24 having a rectangular shape extending in the Z-axis direction from the upper surface of one end in the Y-axis direction of the base 14 and movably in the Z-axis direction. A rectangular Z-axis movable plate 26 and a Z-axis direction moving mechanism 28 for moving the Z-axis movable plate 26 in the Z-axis direction. A pair of guide rails 24 a extending in the Z-axis direction with an interval in the X-axis direction are attached to one side surface (front surface in FIG. 2) of the mounting wall 24. The Z-axis direction movable plate 26 is formed with a pair of guided rails 26 a extending in the Z-axis direction corresponding to the respective guide rails 24 a of the mounting wall 24. The guided rail 26a of the Z-axis direction movable plate 26 is engaged with the guide rail 24a of the mounting wall 24, so that the Z-axis direction movable plate 26 is mounted on the mounting wall 24 so as to be movable in the Z-axis direction. . The Z-axis direction moving mechanism 28 includes a ball screw 30 extending in the Z-axis direction along one side surface of the mounting wall 24, and a motor 32 connected to one end portion of the ball screw 30. A nut portion (not shown) of the ball screw 30 is fixed to the Z-axis direction movable plate 26. Then, the Z-axis direction moving mechanism 28 converts the rotational motion of the motor 32 into a linear motion by the ball screw 30 and transmits it to the Z-axis direction movable plate 26, and along the guide rail 24 a of the mounting wall 24, the Z-axis direction movable plate. 26 is moved in the Z-axis direction.

  2 and FIG. 3, the description of the flattening means 6 will be continued. On the outer surface of the Z-axis direction movable plate 26, a support block 34 protruding in the Y-axis direction is fixed. A motor 36 is supported on the upper surface of the support block 34, and a cylindrical spindle housing 38 extending downward is supported on the lower surface of the support block 34. A cylindrical spindle 40 is rotatably supported on the spindle housing 38 so as to be rotatable about an axis extending in the Z-axis direction. The upper end of the spindle 40 is connected to the motor 36, and the spindle 40 is rotated by the motor 36 about an axis extending in the Z-axis direction. As shown in FIG. 3, a disc-shaped wheel mount 42 is fixed to the lower end of the spindle 40. An annular grinding wheel 46 is fixed to the lower surface of the wheel mount 42 by bolts 44. A plurality of grinding wheels 48 that are annularly arranged at intervals in the circumferential direction are fixed to the outer peripheral edge of the lower surface of the grinding wheel 46. As shown in FIG. 3, when the chuck table 20 is positioned at the flattening position P <b> 2, the rotation center of the grinding wheel 46 is set to the rotation center of the chuck table 20 so that the grinding wheel 48 passes through the rotation center of the chuck table 20. It is displaced with respect to it. Therefore, in the flattening means 6, when the upper surface of the ingot held by the chuck table 20 and the grinding wheel 48 come into contact with each other while the chuck table 20 and the grinding wheel 46 rotate, the entire upper surface of the ingot is ground on the grinding wheel 48. Therefore, the upper surface of the ingot held on the chuck table 20 can be ground and flattened.

  The wafer generating apparatus 2 preferably includes a cleaning unit 50 that cleans the ingot flattened by the flattening unit 6. In the illustrated embodiment, as shown in FIG. 2, the cleaning means 50 includes a support body 52 mounted on the upper surface of the base 14 along the side surface of the mounting wall 24 of the flattening means 6, and an upper portion of the support body 52. It has the 1st washing | cleaning part 54 extended in an axial direction, and the 2nd washing | cleaning part 56 extended in the Y-axis direction from the upper part of the support body 52 along with the 1st washing | cleaning part 54. As shown in FIG. A plurality of injection holes (not shown) are formed at intervals in the Y-axis direction on the lower surface of the first cleaning unit 54 that can be formed from a hollow member. To the cleaning water supply means (not shown). In addition, a plurality of injection holes (not shown) are formed at intervals in the Y-axis direction on the lower surface of the second cleaning unit 56 that can be formed from a hollow member. It is connected to a compressed air source (not shown) by a flow path. In the cleaning means 50, as shown in FIG. 4, the grinding waste is removed from the ingot by injecting the cleaning water 55 while inclining downward from the respective injection holes of the first cleaning portion 54 toward the flattening means 6. The ingot flattened by the flattening means 6 is cleaned by removing the cleaning water 55 from the ingot by removing and spraying the compressed air 57 downward from each spray hole of the second cleaning unit 56. Can do.

  The laser irradiation means 8 will be described with reference to FIGS. The laser irradiation means 8 includes a frame 58 extending upward from the upper surface of the base 14 along with the mounting wall 24 of the flattening means 6, a rectangular guide plate 60 extending in the Y-axis direction from the top of the frame 58, A Y-axis direction movable member 62 supported by the guide plate 60 so as to be movable in the Y-axis direction, and a Y-axis direction moving mechanism 64 for moving the Y-axis direction movable member 62 in the Y-axis direction are included. A pair of guide rails 60 a extending in the Y-axis direction are formed at the lower portions of both ends of the guide plate 60 in the X-axis direction. As shown in FIG. 6, the Y-axis direction movable member 62 is mounted between a pair of guided portions 66 spaced apart in the X-axis direction and between the lower ends of the guided portions 66 and extending in the X-axis direction. Part 68. A guided rail 66 a extending in the Y-axis direction is formed on the top of each guided portion 66. When the guided rail 66a of the guided portion 66 and the guide rail 60a of the guide plate 60 are engaged, the Y-axis direction movable member 62 is supported by the guide plate 60 so as to be movable in the Y-axis direction. In addition, a pair of guide rails 68 a extending in the X-axis direction are formed at both lower portions in the Y-axis direction of the mounting portion 68. As shown in FIG. 6, the Y-axis direction moving mechanism 64 includes a ball screw 70 that extends in the Y-axis direction below the guide plate 60, and a motor 72 that is connected to one end of the ball screw 70. A gate-shaped nut portion 70 a of the ball screw 70 is fixed to the upper surface of the mounting portion 68. The Y-axis direction moving mechanism 64 converts the rotational motion of the motor 72 into a linear motion by the ball screw 70 and transmits it to the Y-axis direction movable member 62, and along the guide rail 60 a of the guide plate 60, the Y-axis direction movable member. 62 is moved in the Y-axis direction.

  The description of the laser irradiation means 8 will be continued with reference to FIG. The laser irradiation means 8 further moves the X-axis direction movable plate 74 mounted on the mounting portion 68 of the Y-axis direction movable member 62 to be movable in the X-axis direction, and the X-axis direction movable plate 74 in the X-axis direction. And an X-axis direction moving mechanism 76. The X-axis direction movable plate 74 is mounted on the mounting portion 68 so as to be movable in the X-axis direction by engaging both ends in the Y-axis direction of the X-axis direction movable plate 74 with the guide rails 68a of the mounting portion 68. . The X-axis direction moving mechanism 76 includes a ball screw 78 that extends in the X-axis direction above the mounting portion 68, and a motor 80 that is connected to one end of the ball screw 78. The nut portion 78 a of the ball screw 78 is fixed to the upper surface of the X-axis direction movable plate 74 through the opening 68 b of the mounting portion 68. The X-axis direction moving mechanism 76 converts the rotational motion of the motor 80 into a linear motion by the ball screw 78 and transmits it to the X-axis direction movable plate 74, and along the guide rail 68 a of the mounting portion 68, the X-axis direction movable plate. 74 is moved in the X-axis direction.

  The description of the laser irradiation means 8 will be continued with reference to FIG. 7 together with FIG. The laser irradiation means 8 further includes a laser oscillator 82 built in the frame body 58, and a first mounted on the lower surface of the mounting portion 68 of the Y-axis direction movable member 62 at a distance from the laser oscillator 82 in the Y-axis direction. The second mirror 84 and the first mirror 84 are spaced from each other in the X-axis direction and mounted on the lower surface of the X-axis direction movable plate 74 directly above the condenser 86 to guide the pulsed laser beam LB to the condenser 86. Mirror (not shown), a concentrator 86 mounted on the lower surface of the X-axis direction movable plate 74 so as to be movable in the Z-axis direction, and a concentrator X spaced apart from the concentrator 86 in the X-axis direction. Alignment means 88 mounted on the lower surface of the axially movable plate 74, and condensing point position adjusting means for adjusting the position of the condensing point of the condenser 86 in the Z-axis direction by moving the condenser 86 in the Z-axis direction. (Not shown). The laser oscillator 82 oscillates a pulsed laser beam LB having a wavelength that is transparent to the ingot. The condenser 86 has a condenser lens (not shown) that collects the pulse laser beam LB oscillated by the laser oscillator 82, and the condenser lens is located below the second mirror. The alignment means 88 detects an area to be laser processed by imaging the ingot held on the chuck table 20. The condensing point position adjusting means includes, for example, a ball screw (not shown) whose nut portion is fixed to the concentrator 86 and extending in the Z-axis direction, and a motor (not shown) connected to one end of the ball screw. It may be a structure having In the condensing point position adjusting means having such a structure, a guide rail (not shown) extending in the Z-axis direction by converting the rotational motion of the motor into a linear motion by a ball screw and transmitting it to the concentrator 86. , And the position of the condensing point of the pulse laser beam LB condensed by the condensing lens is adjusted. Then, the pulse laser beam LB oscillated from the laser oscillator 82 with the optical axis set in the Y-axis direction is converted from the Y-axis direction to the X-axis direction by the first mirror 84 and guided to the second mirror. Next, the optical axis is converted from the X-axis direction to the Z-axis direction by the second mirror and guided to the condensing lens of the concentrator 86, and then condensed by the condensing lens of the concentrator 86 and chucked. The ingot held on the table 20 is irradiated. Further, even when the concentrator 86 is moved in the Y-axis direction by moving the Y-axis direction movable member 62 by the Y-axis direction moving mechanism 64, the X-axis direction movable plate is also moved by the X-axis direction moving mechanism 76. Even when the condenser 86 is moved in the X-axis direction by moving 74, the pulse laser beam LB oscillated from the oscillator 82 in parallel with the Y-axis direction is changed in the Y-axis direction by the first mirror 84. Is converted in the X-axis direction and guided to the second mirror, and the pulse laser beam LB guided to the second mirror is converted from the X-axis direction to the Z-axis direction by the second mirror so that the light collector 86. In the laser irradiation means 8 configured as described above, the ingot held on the chuck table 20 is imaged by the alignment means 88 to detect the region to be laser processed, and the condenser 86 is adjusted by the condensing point position adjusting means. The condensing point of the pulsed laser beam LB having a wavelength transmissive to the ingot is positioned at a depth corresponding to the thickness of the wafer to be generated from the upper surface of the ingot held on the chuck table 20 by moving in the Z-axis direction. The X-axis direction moving mechanism 76 appropriately moves the X-axis direction movable plate 74 and the Y-axis direction moving mechanism 64 appropriately moves the Y-axis direction movable member 62 in the Y-axis direction. By irradiating the ingot with the pulsed laser beam LB, a release layer can be formed inside the ingot.

  The wafer peeling means 10 will be described with reference to FIGS. The wafer peeling means 10 for applying ultrasonic vibration to the ingot formed with the peeling layer by the laser irradiation means 8 and peeling the wafer from the ingot starting from the peeling layer includes a support 90 fixed to the upper surface of the base 14 and , An arm 92 extending in the X-axis direction from a base end portion supported by the support 90 so as to be movable in the Z-axis direction, and an arm moving mechanism 94 for moving the arm 92 in the Z-axis direction. The arm moving mechanism 94 includes a ball screw (not shown) extending in the Z-axis direction inside the support 90 and a motor 96 connected to one end of the ball screw. A ball screw nut (not shown) of the arm moving mechanism 94 is fixed to the base end of the arm 92. The arm moving mechanism 94 converts the rotational motion of the motor 96 into a linear motion using a ball screw and transmits the linear motion to the arm 92, and a guide rail (not shown) extending in the Z-axis direction built in the support 90. The arm 92 is moved in the Z-axis direction along the direction.

  The description of the wafer peeling means 10 will be continued with reference to FIGS. A liquid tank body 98 that holds liquid in cooperation with the chuck table 20 when the wafer is peeled from the ingot is fixed to the tip of the arm 92. The liquid tank body 98 has a circular top wall 100 and a cylindrical side wall 102 depending from the periphery of the top wall 100, and the lower end side is open. The top wall 100 is provided with a cylindrical liquid supply unit 104 that communicates the outside and the inside of the liquid tank body 98. The liquid supply unit 104 is connected to liquid supply means (not shown) by a flow path. Further, as shown in FIG. 9, an annular packing 106 is attached to the lower end of the side wall 102. When the arm 92 is lowered by the arm moving mechanism 94 to bring the lower end of the side wall 102 into close contact with the upper surface of the chuck table 20, the liquid storage space 108 is defined by the upper surface of the chuck table 20 and the inner surface of the liquid tank body 98. . The liquid 110 supplied from the liquid supply means through the liquid supply unit 104 to the liquid storage space 108 is prevented from leaking from the liquid storage space 108 by the packing 106.

  If the description of the wafer peeling means 10 is further continued with reference to FIGS. 8 and 9, an air cylinder 112 is mounted on the top wall 100 of the liquid tank body 98. The cylinder tube 112 a of the air cylinder 112 extends upward from the upper surface of the top wall 100. As shown in FIG. 9, the lower end portion of the piston rod 112 b of the air cylinder 112 passes through the through-opening 100 a of the top wall 100 and protrudes below the top wall 100. A disc-shaped ultrasonic vibration generating member 114 that can be formed of piezoelectric ceramics or the like is fixed to the lower end portion of the piston rod 112b. A disk-shaped suction piece 116 is fixed to the lower surface of the ultrasonic vibration generating member 114. The suction piece 116 having a plurality of suction holes (not shown) formed on the lower surface is connected to suction means (not shown) by a flow path. By generating a suction force on the lower surface of the suction piece 116 by the suction means, the suction piece 116 can suck and hold the ingot. In the wafer peeling means 10, the arm 92 is moved down by the arm moving mechanism 94, and the lower end of the side wall 102 is brought into close contact with the upper surface of the chuck table 20 holding the ingot on which the peeling layer is formed by the laser irradiation means 8. The piston rod 112b of the cylinder 112 is lowered to adsorb the adsorbing piece 116 on the upper surface of the ingot, and after the liquid 110 is accommodated in the liquid accommodating space 108, the ultrasonic vibration generating member 114 is operated to generate ultrasonic waves on the ingot. By imparting vibration, the wafer can be peeled from the ingot starting from the peeling layer.

  The wafer accommodating means 12 will be described with reference to FIGS. The wafer accommodating means 12 is composed of a cassette that can accommodate a plurality of wafers separated from the ingot starting from the peeling layer by the wafer peeling means 10 at intervals in the vertical direction, and is detachably mounted on the upper surface of the base 14. Has been. Further, between the wafer peeling means 10 and the wafer accommodating means 12, a wafer conveying means 118 for conveying the wafer peeled from the ingot by the wafer peeling means 10 from the peeling layer as a starting point from the wafer peeling means 10 to the wafer accommodating means 12. Is arranged. As shown in FIG. 2, the wafer transport unit 118 is centered on an elevating unit 120 extending upward from the upper surface of the base 14, a first motor 122 fixed to the tip of the elevating unit 120, and an axis extending in the Z-axis direction. A first arm 124 having a base end connected to the first motor 122 to be freely rotatable, a second motor 126 fixed to the tip of the first arm 124, and an axis extending in the Z-axis direction. A second arm 128 having a base end connected to the second motor 126 so as to be rotatable about the center, and a suction piece 130 on a disc fixed to the tip of the second arm 128 are included. The first motor 122 moved up and down in the Z-axis direction by the lifting / lowering means 120 has a first arm with respect to the lifting / lowering means 120 about an axis extending in the Z-axis direction through the proximal end portion of the first arm 124. 124 is rotated. The second motor 126 rotates the second arm 128 relative to the first arm 124 about an axis extending in the Z-axis direction through the proximal end portion of the second arm 128. The suction piece 130 having a plurality of suction holes 130a formed on the upper surface is connected to suction means (not shown) by a flow path. In the wafer transport unit 118, the suction unit 130 generates a suction force on the upper surface of the suction piece 130, and the wafer release unit 10 sucks the wafer peeled off the ingot from the release layer as a starting point. The wafers adsorbed by the adsorbing pieces 130 can be separated by operating the first arm 124 and the second arm 128 by the lifting means 120, the first motor 122 and the second motor 126. It can be transferred from the means 10 to the wafer accommodating means 12.

  As shown in FIG. 1, it is preferable that the wafer generating apparatus 2 further includes an ingot accommodating means 132 that accommodates an ingot, and an ingot conveying means 134 that conveys the ingot from the ingot accommodating means 132 to the holding means 4. The ingot accommodating means 132 in the illustrated embodiment is composed of four circular accommodating recesses 132a formed on the upper surface of the base 14 at intervals in the Y-axis direction. An ingot is accommodated in each of the four accommodating recesses 132a having a diameter slightly larger than the diameter of the ingot.

  The ingot conveying means 134 will be described with reference to FIGS. The ingot conveying means 134 includes a frame body 136 extending in the Y-axis direction along the ingot housing means 132 on the upper surface of the base 14, and a base end portion supported by the frame body 136 movably in the Y-axis direction from the X-axis direction. And an arm moving mechanism 140 that moves the arm 138 in the Y-axis direction. In the frame 136, a rectangular guide opening 136a extending in the Y-axis direction is formed. The arm moving mechanism 140 includes a ball screw (not shown) extending in the Y-axis direction inside the frame 136 and a motor 142 coupled to one end of the ball screw. A ball screw nut portion (not shown) of the arm moving mechanism 140 is fixed to the base end portion of the arm 138. The arm moving mechanism 140 converts the rotational motion of the motor 142 into a linear motion using a ball screw and transmits it to the arm 138, and moves the arm 138 in the Y-axis direction along the guide opening 136a of the frame 136. As shown in FIG. 10, an air cylinder 144 extending in the Z-axis direction is attached to the distal end portion of the arm 138, and a disc-shaped suction piece 146 is fixed to the lower end portion of the piston rod 144 a of the air cylinder 144. The suction piece 146 in which a plurality of suction holes (not shown) are formed on the lower surface is connected to suction means (not shown) by a flow path. In the ingot conveying means 134, the suction means generates suction force on the lower surface of the suction piece 146, so that the upper surface of the ingot accommodated in the ingot accommodation means 132 can be attracted and held by the suction piece 146. In addition, the arm 138 is moved by the arm moving mechanism 140 and the suction piece 146 is moved by the air cylinder 144, whereby the ingot held by the suction piece 146 can be conveyed from the ingot housing means 132 to the holding means 4. .

  FIG. 11 shows an ingot 150 that can be processed by the wafer generator 2 as described above. The illustrated ingot 150 is formed in a cylindrical shape as a whole from hexagonal single crystal SiC, and includes a circular first surface 152 and a circular second surface 154 opposite to the first surface 152. , A peripheral surface 156 positioned between the first surface 152 and the second surface 154, a c-axis (<0001> direction) from the first surface 152 to the second surface 154, and orthogonal to the c-axis c plane ({0001} plane). In the illustrated ingot 150, the c-axis is inclined with respect to the normal 158 of the first surface 152, and the off-angle α (for example, α = 1, 3, 6 degrees) between the c surface and the first surface 152. Is formed. The direction in which the off angle α is formed is indicated by an arrow A in FIG. In addition, a rectangular first orientation flat 160 and a second orientation flat 162 indicating the crystal orientation are formed on the peripheral surface 156 of the ingot 150. The first orientation flat 160 is parallel to the direction A in which the off angle α is formed, and the second orientation flat 162 is orthogonal to the direction A in which the off angle α is formed. As shown in FIG. 11B, when viewed from above, the length L2 of the second orientation flat 162 is shorter than the length L1 of the first orientation flat 160 (L2 <L1). The ingot that can be processed by the wafer generator 2 is not limited to the ingot 150. For example, the c-axis is not inclined with respect to the normal of the first surface, and the c-surface and the first surface May be a single crystal SiC ingot having a 0-degree off-angle (that is, the perpendicular to the first surface coincides with the c-axis), or formed of a material other than single crystal SiC such as GaN (gallium nitride). It may be an ingot.

  A wafer generation method for generating a wafer from the ingot 150 using the wafer generation apparatus 2 as described above will be described. In the wafer generating method using the wafer generating device 2, first, four ingots 150 are prepared, and as shown in FIG. 12, an end face (for example, the second surface 154) of each prepared ingot 150 is interposed with an appropriate adhesive. Then, a substrate mounting process for mounting the disk-shaped substrate 164 is performed. The substrate mounting process is performed by adsorbing and holding the ingot 150 formed with the first orientation flat 160 and the second orientation flat 162 with a predetermined suction force by the circular suction chuck 22 of the chuck table 20. It is to do. The diameter of the substrate 164 is slightly larger than the diameter of the ingot 150 and slightly larger than the diameter of the suction chuck 22 of the chuck table 20. Then, since the suction chuck 22 is covered with the substrate 164 when the ingot 150 is placed on the chuck table 20 with the substrate 164 facing downward, when the suction means connected to the suction chuck 22 is operated, the suction chuck 22 Thus, the substrate 164 is adsorbed with a predetermined suction force, whereby the ingot 150 formed with the first orientation flat 160 and the second orientation flat 162 can be held by the chuck table 20. If the diameter of the ingot is larger than that of the suction chuck 22 and the entire top surface of the suction chuck 22 is covered with the ingot when the ingot is placed on the chuck table 20, the suction chuck 22 is sucked by the suction chuck 22. Since the air is not sucked from the exposed portion and the ingot can be sucked by the suction chuck 22 with a predetermined suction force, the substrate mounting step does not have to be performed.

  After performing the substrate mounting process, the ingot accommodating process of accommodating the ingot 150 in the ingot accommodating means 132 is performed. In the illustrated embodiment, as shown in FIG. 1, in the ingot housing process, the four ingots 150 are housed in the four housing recesses 132 a of the ingot housing means 132 with the substrate 164 facing downward.

  After performing the ingot accommodation process, the ingot conveyance process which conveys the ingot 150 from the ingot accommodation means 132 to the holding means 4 by the ingot conveyance means 134 is performed. In the ingot conveying step, first, the arm 138 is moved in the Y-axis direction by the arm moving mechanism 140 of the ingot conveying means 134, and any one ingot 150 among the four ingots 150 accommodated in the ingot accommodating means 132 is used. The suction piece 146 is positioned above (hereinafter referred to as “first ingot 150a”). Next, the suction piece 146 is lowered by the air cylinder 144 of the ingot conveying means 134, and the lower surface of the suction piece 146 is brought into close contact with the upper surface (for example, the first surface 152) of the first ingot 150a. Next, the suction means connected to the suction piece 146 is operated to generate a suction force on the lower surface of the suction piece 146, and the lower surface of the suction piece 146 is sucked onto the upper surface of the first ingot 150a. Next, the suction piece 146 that sucks the first ingot 150 a is raised by the air cylinder 144. Next, the arm 138 is moved in the Y-axis direction by the arm moving mechanism 140, and the suction piece 146 that sucks the first ingot 150a is positioned above the chuck table 20 positioned at the standby position P1. Next, as shown in FIG. 13, the suction piece 146 sucking the first ingot 150a is lowered by the air cylinder 144, and the lower surface of the substrate 164 is brought into contact with the upper surface of the chuck table 20 positioned at the standby position P1. Then, the operation of the suction means connected to the suction piece 146 is stopped to release the suction force of the suction piece 146, and the first ingot 150a is placed on the upper surface of the chuck table 20 positioned at the standby position P1. As a result, the first ingot 150 a can be conveyed by the ingot conveying means 134 from the ingot accommodating means 132 to the chuck table 20 constituting the holding means 4.

  After performing an ingot conveyance process, the holding process which hold | maintains the ingot 150 with the holding means 4 is implemented. In the holding step, the suction means connected to the suction chuck 22 on which the first ingot 150a is placed is operated to generate a suction force on the upper surface of the suction chuck 22, and the first ingot 150a is sucked by the chuck table 20. Hold.

  After carrying out the holding step, the turntable 18 is rotated by 90 degrees clockwise as viewed from above by the turntable motor, and the chuck table 20 adsorbing the first ingot 150a is moved to the standby position as shown in FIG. Move from P1 to the flattening position P2. For the first ingot 150a positioned at the flattening position P2, the flattening process of grinding and flattening the upper surface of the ingot 150 held by the holding means 4 may not be performed at this stage. The ingot 150 is usually transported from the ingot accommodating means 132 because the end surfaces (the first surface 152 and the second surface 154) are flattened to such an extent that the incidence of the laser beam in the peeling layer forming step described later is not hindered. Then, it is not necessary to perform the flattening process on the ingot 150 that is first positioned at the flattening position P2. Then, the ingot conveying means 134 performs the ingot conveying process on any one ingot 150 (hereinafter referred to as “second ingot 150 b”) among the remaining three ingots 150 accommodated in the ingot accommodating means 132. At the same time, a holding step of holding the chuck table 20 positioned at the standby position P1 is performed. In FIG. 14, for convenience, the first ingot 150a located at the flattening position P2 and the second ingot 150b located at the standby position P1 are shown in the same direction. Due to the rotation of the chuck table 20, the ingot 150 attracted to the chuck table 20 is in an arbitrary direction, and this point is the same in FIG.

  After performing the ingot conveyance process and the holding process for the second ingot 150b, the turntable 18 is rotated by 90 degrees clockwise as viewed from above by the turntable motor. As a result, as shown in FIG. 15, the chuck table 20 adsorbing the first ingot 150a is moved from the flattening position P2 to the release layer forming position P3 and the chuck table 20 adsorbing the second ingot 150b. Is moved from the standby position P1 to the flattening position P2. And about the 1st ingot 150a, the condensing point of the laser beam of the wavelength which has the transmittance | permeability with respect to the ingot 150 to the depth equivalent to the thickness of the wafer which should be produced | generated from the upper surface of the ingot 150 hold | maintained at the holding means 4 The release layer forming step of forming a release layer by irradiating the ingot 150 with a laser beam is performed by the laser irradiation means 8. On the other hand, since the second ingot 150b is transported from the ingot accommodating means 132 as described above and is initially positioned at the flattening position P2, the flattening step need not be performed. In addition, the ingot transfer unit 134 performs an ingot transfer process on any one ingot 150 (hereinafter referred to as “third ingot 150 c”) of the remaining two ingots 150 stored in the ingot storage unit 132. At the same time, a holding step of holding the chuck table 20 positioned at the standby position P1 is performed.

  The peeling layer formation process implemented by the laser irradiation means 8 is demonstrated. In the peeling layer forming step in the illustrated embodiment, first, the X-axis direction movable plate 74 is moved by the X-axis direction moving mechanism 76 (see FIGS. 5 and 6) of the laser irradiation means 8 and the Y-axis direction moving mechanism 64 is moved. The Y-axis direction movable member 62 is moved in the Y-axis direction, the alignment unit 88 is positioned above the ingot 150, and the ingot 150 is imaged by the alignment unit 88 from above the ingot 150. Next, based on the image of the ingot 150 imaged by the alignment means 88, the chuck table 20 is rotated by the chuck table motor, and the X-axis direction movable plate 74 is moved by the X-axis direction moving mechanism 76 and the Y-axis direction. The moving mechanism 64 moves the Y-axis direction movable member 62 in the Y-axis direction, thereby adjusting the direction of the ingot 150 to a predetermined direction and adjusting the positions of the ingot 150 and the condenser 86 in the XY plane. When adjusting the orientation of the ingot 150 to a predetermined orientation, as shown in FIG. 16A, the first orientation flat 160 is aligned in the Y-axis direction and the second orientation flat 162 is aligned in the X-axis direction. By doing so, the direction A in which the off angle α is formed is aligned with the Y axis direction, and the direction orthogonal to the direction A in which the off angle α is formed is aligned with the X axis direction. Next, the concentrator 86 is moved in the Z-axis direction by the condensing point position adjusting means, and should be generated from the upper surface of the ingot 150 (the first surface 152 in the illustrated embodiment) as shown in FIG. The condensing point FP is positioned at a depth corresponding to the thickness of the wafer. Next, by moving the X-axis direction movable plate 74 by the X-axis direction moving mechanism 76, relative to the ingot 150 in the X-axis direction aligned with the direction orthogonal to the direction A in which the off angle α is formed. Then, the release layer is formed by irradiating the ingot 150 with the pulse laser beam LB having a wavelength that is transmissive to the ingot 150 while moving the condensing point FP at a predetermined feed rate.

  When the release layer forming process is performed, as shown in FIGS. 17A and 17B, the SiC is separated into Si (silicon) and C (carbon) by the irradiation of the pulse laser beam LB, and then the pulse is irradiated. The laser beam LB is absorbed by the previously formed C, and the linearly modified layer 166 is formed by separating SiC into Si and C in a chain, and the modified layer 166 is modified along the c-plane. Cracks 168 that propagate on both sides of layer 166 are formed. In the peeling layer forming process, the condensing point FP is processed relative to the ingot 150 in the X-axis direction so that adjacent spots of the pulsed laser beam LB overlap each other at the depth at which the modified layer 166 is formed. The ingot 150 is irradiated with the pulse laser beam LB while being fed so that the modified layer 166 separated into Si and C is irradiated with the pulse laser beam LB again. In order for adjacent spots to overlap each other, G = (V / F) −D defined by the repetition frequency F of the pulse laser beam LB, the feed speed V of the condensing point FP, and the spot diameter D is G <0. It is necessary to be. Further, the overlapping rate of adjacent spots is defined by | G | / D.

16 and FIG. 17, in the release layer forming process, following the release layer forming process, the Y-axis direction movable member 62 is moved by the Y-axis direction moving mechanism 64 so that the off angle α is The condensing point FP is indexed by a predetermined index amount Li relative to the ingot 150 in the Y-axis direction aligned with the formed direction A. Then, by repeatedly repeating the release layer forming process and index feeding in the release layer forming step, the linear modified layer 166 extending along the direction orthogonal to the direction A in which the off angle α is formed is changed to the off angle. A plurality of cracks 168 are formed in the direction A in which α is formed, with an interval of a predetermined index amount Li, and adjacent cracks 168 and 168 overlap in the direction A in which the off angle α is formed. As a result, the release layer 170 for peeling the wafer from the ingot 150, which includes a plurality of modified layers 166 and cracks 168, is formed at a depth corresponding to the thickness of the wafer to be generated from the upper surface of the ingot 150. it can. The release layer forming step for forming the release layer 170 on the ingot 150 can be performed, for example, under the following processing conditions.
Pulse laser beam wavelength: 1064 nm
Repetition frequency: 80 kHz
Average output: 3.2W
Pulse width: 4 ns
Condensing point diameter: 3 μm
Numerical aperture (NA) of condenser lens: 0.43
Z-axis direction position of the focal point: 300 μm from the top surface of the ingot
Converging point feed speed: 120 to 260 mm / s
Index amount: 250 to 400 μm

  After performing the peeling layer forming process for the first ingot 150a and performing the ingot transporting process and the holding process for the third ingot 150c, the turntable 18 is rotated by 90 degrees clockwise as viewed from above with the turntable motor. Rotate. As a result, as shown in FIG. 18, the chuck table 20 adsorbing the first ingot 150a on which the release layer 170 is formed is moved from the release layer forming position P3 to the wafer release position P4, and the second ingot 150b is adsorbed. The chuck table 20 being moved is moved from the flattening position P2 to the release layer forming position P3, and the chuck table 20 adsorbing the third ingot 150c is moved from the standby position P1 to the flattening position P2. For the first ingot 150a, the wafer peeling means 10 performs a wafer peeling process for holding the upper surface of the ingot 150 and peeling the wafer from the peeling layer 170. For the second ingot 150b, the peeling layer forming step is performed by the laser irradiation means 8. On the other hand, since the third ingot 150c is transported from the ingot accommodating means 132 as described above and is initially positioned at the flattening position P2, the flattening step need not be performed. The remaining one ingot 150 (hereinafter referred to as “fourth ingot 150d”) accommodated in the ingot accommodating means 132 is subjected to the ingot conveying process by the ingot conveying means 134 and is positioned at the standby position P1. A holding step of holding the chuck table 20 is performed.

  With reference to FIG. 9, FIG. 19, and FIG. 20, the wafer peeling process performed by the wafer peeling means 10 will be described. In the wafer peeling process in the illustrated embodiment, first, as shown in FIGS. 19A and 19B, the arm 92 is lowered by the arm moving mechanism 94 to hold the ingot 150 on which the peeling layer 170 is formed. The lower end of the side wall 102 of the liquid tank body 98 is brought into close contact with the upper surface of the chuck table 20. Next, as shown in FIG. 9, the piston rod 112 b of the air cylinder 112 of the wafer peeling means 10 is moved to bring the lower surface of the suction piece 116 into close contact with the upper surface of the ingot 150. Next, the suction means connected to the suction piece 116 is operated to generate a suction force on the lower surface of the suction piece 116, and the lower surface of the suction piece 116 is sucked and held on the upper surface of the ingot 150. Next, the liquid supply means connected to the liquid supply unit 104 is operated, and the liquid 110 (for example, water) is supplied from the liquid supply unit 104 to the liquid storage space 108 until the ultrasonic vibration generating member 114 is immersed. Next, when the ultrasonic vibration generating member 114 is operated and ultrasonic vibration is applied to the ingot 150, the wafer 172 to be generated from the ingot 150 can be peeled from the peeling layer 170 as a starting point. Next, the arm 92 is raised by the arm moving mechanism 94, and the liquid 110 is discharged from the liquid storage space 108. The liquid 110 discharged from the liquid storage space 108 passes through the drain port 16a (see FIG. 2) formed adjacent to the wafer peeling means 10 in the turntable storage portion 16 of the base 14 and is supplied to the wafer generator 2. It is discharged outside. Then, as shown in FIG. 20, the piston rod 112 b of the air cylinder 112 is lowered until the wafer 172 generated from the ingot 150 protrudes downward from the lower end of the side wall 102 of the liquid tank body 98. As shown in FIG. 20, the peeling surface 174 of the ingot 150 from which the wafer 172 has been peeled is uneven, and the height of the unevenness of the peeling surface 174 is, for example, about 100 μm.

  After carrying out the wafer peeling process on the first ingot 150a, the wafer carrying means 118 carries out a wafer carrying process in which the wafer 172 generated from the first ingot 150a is carried from the wafer peeling means 10 to the wafer containing means 12 and accommodated. To do. In the wafer transporting process, the first arm 122 is operated by the first motor 122 of the wafer transporting unit 118 and the second arm 128 is operated by the second motor 126 and is peeled off by the wafer peeling unit 10 and is adsorbed. The suction piece 130 of the wafer conveying means 118 is positioned below the wafer 172 sucked by the 116. Next, the lifting / lowering means 120 of the wafer transport means 118 is operated to bring the upper surface of the suction piece 130 of the wafer transport means 118 into close contact with the lower surface of the wafer 172. Next, the suction means connected to the suction piece 116 of the wafer peeling means 10 is stopped to release the suction force of the suction piece 116 of the wafer peeling means 10 and connected to the suction piece 130 of the wafer transport means 118. The suction means is operated to generate a suction force on the upper surface of the suction piece 130 of the wafer transport means 118, and the lower surface of the wafer 172 is attracted to the upper surface of the suction piece 130 of the wafer transport means 118. As a result, the wafer 172 is transferred from the wafer peeling means 10 to the wafer transport means 118. Next, the first arm 124 and the second arm 128 are operated by the lifting / lowering means 120, the first motor 122, and the second motor 126 of the wafer transport means 118, so that the suction pieces 130 of the wafer transport means 118 are attracted. The wafer 172 can be transferred from the wafer peeling means 10 to the wafer storage means 12 and stored therein.

  A wafer peeling process is performed on the first ingot 150a, a wafer transporting process is performed on the wafer 172 generated from the first ingot 150a, a peeling layer forming process is performed on the second ingot 150b, and a fourth After performing the ingot conveyance process and the holding process for the ingot 150d, the turntable 18 is rotated by 90 degrees clockwise as viewed from above by the turntable motor. As a result, as shown in FIG. 21, the chuck table 20 sucking the first ingot 150a is moved from the wafer peeling position P4 to the standby position P1, and the chuck table 20 sucking the second ingot 150b is moved to the peeling layer. The chuck table 20 that has attracted the third ingot 150c is moved from the forming position P3 to the wafer peeling position P4, and is moved from the flattening position P2 to the peeling layer forming position P3, and the fourth ingot 150d is sucked. The chuck table 20 being moved is moved from the standby position P1 to the flattening position P2. For the second ingot 150b, the wafer peeling process is performed by the wafer peeling means 10, and for the wafer 172 generated from the second ingot 150b, the wafer conveying process is performed by the wafer conveying means 118. For the third ingot 150c, the peeling layer forming step is performed by the laser irradiation means 8. On the other hand, the fourth ingot 150d is transported from the ingot accommodating means 132 as described above and is initially positioned at the flattening position P2, so that it is not necessary to perform the flattening step. The first ingot 150a positioned at the standby position P1 waits at the standby position P1 until the turntable 18 is next rotated.

  After the wafer peeling process is performed for the second ingot 150b, the wafer transport process is performed for the wafer 172 generated from the second ingot 150b, and the peeling layer forming process is performed for the third ingot 150c. As a result, the turntable 18 is rotated 90 degrees clockwise by the turntable motor. As a result, as shown in FIG. 22, the chuck table 20 adsorbing the first ingot 150a is moved from the standby position P1 to the flattening position P2, and the chuck table 20 adsorbing the second ingot 150b is removed from the wafer. The chuck table 20 that has attracted the third ingot 150c is moved from the position P4 to the standby position P1, and is moved from the release layer forming position P3 to the wafer peeling position P4, and the fourth ingot 150d is sucked. The chuck table 20 is moved from the flattening position P2 to the release layer forming position P3. For the first ingot 150a, the flattening means 6 performs a flattening process for grinding and flattening the upper surface of the ingot 150 held by the holding means 4. For the third ingot 150c, the wafer peeling process is performed by the wafer peeling means 10, and for the wafer 172 generated from the third ingot 150c, the wafer conveying process is performed by the wafer conveying means 118. For the fourth ingot 150 d, the peeling layer forming step is performed by the laser irradiation means 8. The second ingot 150b positioned at the standby position P1 waits at the standby position P1 until the turntable 18 is next rotated.

  With reference to FIG. 3, the planarization process implemented by the planarization means 6 is demonstrated. In the flattening step, first, the chuck table 20 holding the ingot 150 from which the wafer 172 has been peeled is rotated counterclockwise by a chuck table motor at a predetermined rotational speed (for example, 300 rpm) as viewed from above. Further, the spindle 40 of the flattening means 6 is rotated by the motor 36 at a predetermined rotational speed (for example, 6000 rpm) counterclockwise when viewed from above. Next, the Z-axis direction movable plate 26 is lowered by the Z-axis direction moving mechanism 28 of the flattening means 6, and the grinding wheel 48 is brought into contact with the peeling surface 174 of the ingot 150. After bringing the grinding wheel 48 into contact with the peeling surface 174, the Z-axis direction movable plate 26 is lowered by the Z-axis direction moving mechanism 28 at a predetermined grinding feed rate (for example, 1.0 μm / s). As a result, the peeling surface 174 of the ingot 150 from which the wafer 172 has been peeled can be ground, and the peeling surface 174 of the ingot 150 can be flattened to such an extent that the incidence of the pulse laser beam LB in the peeling layer forming process is not hindered. When the peeling surface 174 of the ingot 150 is ground and flattened, a thickness measuring device (not shown) is brought into contact with the peeling surface 174 of the ingot 150, and the thickness of the ingot 150 measured by the thickness measuring device is determined. When it is detected that a fixed amount (for example, 100 μm of the uneven height of the peeling surface 174) has been reduced, it can be detected that the upper surface of the ingot 150 has been flattened. Further, in the flattening step, when the peeling surface 174 of the ingot 150 is ground, the grinding water is supplied from the grinding water supply means (not shown) to the grinding area, and is supplied to the grinding area. The grinding water is discharged to the outside of the wafer generator 2 through a drain port 16b (see FIG. 2) formed adjacent to the flattening means 6 in the turntable accommodating portion 16 of the base 14.

  A flattening step is performed on the first ingot 150a, a wafer peeling step is performed on the third ingot 150c, a wafer transfer step is performed on the wafer 172 generated from the third ingot 150c, and a fourth ingot is formed. After performing the peeling layer forming step for 150d, the turntable 18 is rotated by 90 degrees clockwise as viewed from above by the turntable motor. As a result, as shown in FIG. 23, the chuck table 20 adsorbing the first ingot 150a is moved from the flattening position P2 to the release layer forming position P3, and the chuck table 20 adsorbing the second ingot 150b is moved. The chuck table 20 that has moved from the standby position P1 to the flattening position P2 and sucks the third ingot 150c is moved from the wafer peeling position P4 to the standby position P1 and sucks the fourth ingot 150d. The chuck table 20 is moved from the peeling layer forming position P3 to the wafer peeling position P4. At this time, as shown in FIG. 4, the cleaning means 50 is operated, and the cleaning water 55 is sprayed from the respective injection holes of the first cleaning portion 54 downwardly to the flattening means 6 side. In addition to removing grinding waste from the ingot 150a, the pressure air 57 is sprayed downward from each injection hole of the second cleaning unit 56 to remove the cleaning water 55 from the first ingot 150a, thereby flattening means. The first ingot 150a flattened by 6 is washed and dried. And about the 1st ingot 150a, the peeling layer formation process is implemented by the laser irradiation means 8. FIG. For the second ingot 150b, the flattening means 6 performs a flattening step. For the fourth ingot 150 d, the wafer peeling process is performed by the wafer peeling means 10, and for the wafer 172 generated from the fourth ingot 150 d, the wafer conveying process is performed by the wafer conveying means 118. The third ingot 150c positioned at the standby position P1 waits at the standby position P1 until the turntable 18 is next rotated.

  Then, by rotating the turntable 18 by 90 degrees clockwise as viewed from above, each chuck table 20 is sequentially moved to the standby position P1, the flattening position P2, the peeling layer forming position P3, and the wafer peeling position P4. Positioning and repeatedly performing a flattening process, a release layer forming process, and a wafer peeling process on each ingot 150 held on each chuck table 20, and a wafer transporting process for each wafer 172 peeled by the wafer peeling means 10. By carrying out, a number of wafers 172 that can be generated from each ingot 150 are generated, and the generated wafers 172 are stored in the wafer storage means 12.

  In the illustrated embodiment, after the number of wafers 172 that can be generated from each ingot 150 is generated, the substrate 164 in which the material of the ingot 150 remains slightly is placed on the upper end of the base 14 by the ingot conveying means 134. A substrate recovery step of transporting and recovering to an appropriate recovery container 176 (see FIGS. 1 and 2) arranged can be performed. In the substrate recovery step, first, the arm 138 is moved in the Y-axis direction by the arm moving mechanism 140 of the ingot transfer means 134, and the suction piece 146 is positioned above the substrate 164 positioned at the standby position P1. Next, the suction piece 146 is lowered by the air cylinder 144 of the ingot conveying means 134, and the lower surface of the suction piece 146 is brought into close contact with the upper surface of the substrate 164. Next, the suction means connected to the suction piece 146 is operated to generate a suction force on the lower surface of the suction piece 146, thereby attracting the lower surface of the suction piece 146 to the upper surface of the substrate 164. Next, the suction piece 146 sucking the substrate 164 is raised by the air cylinder 144. Next, the arm 138 is moved in the Y-axis direction by the arm moving mechanism 140, and the suction piece 146 is positioned above the collection container 176. Next, the operation of the suction means connected to the suction piece 146 is stopped, the suction force of the suction piece 146 is released, and the substrate 164 is accommodated in the collection container 176. Then, the turntable is rotated by the turntable motor, and the substrate recovery process is performed on the substrate 164 sequentially positioned at the standby position P1, whereby all the substrates 164 are transported to the recovery container 176 and recovered. be able to.

  As described above, in the illustrated embodiment, the holding means 4 that holds the ingot 150, the flattening means 6 that grinds and flattens the upper surface of the ingot 150 held by the holding means 4, and the holding means 4 holds the ingot 150. The condensing point FP of the pulsed laser beam LB having a wavelength that is transparent to the ingot 150 is positioned at a depth corresponding to the thickness of the wafer 172 to be generated from the upper surface of the ingot 150, and the ingot 150 is irradiated with the pulsed laser beam LB to be peeled The laser irradiation means 8 for forming the layer 170, the wafer peeling means 10 for holding the upper surface of the ingot 150 and peeling the wafer 172 from the peeling layer 170, and the wafer accommodating means 12 for accommodating the peeled wafer 172 are at least configured. As described above, a peeling layer forming process, a wafer peeling process, a wafer transport process and By sequentially performing the planarization process, it is possible to automatically generate the wafer 172 from the ingot 150 is accommodated in the wafer accommodation unit 12, thus the production efficiency is improved.

  In the illustrated embodiment, since the ingot accommodating means 132 for accommodating the ingot 150 and the ingot conveying means 134 for conveying the ingot 150 from the ingot accommodating means 132 to the holding means 4 are included, the ingot 150 is accommodated in the ingot accommodating means 132. Thus, by operating the wafer generator 2, it is possible to automate the ingot transfer process of transferring the ingot 150 from the ingot storage means 132 to the holding means 4.

  Further, in the illustrated embodiment, the cleaning means 50 for cleaning the ingot 150 flattened by the flattening means 6 is included, so that the cleaning means 50 is used when the peeling surface 174 of the ingot 150 is ground in the flattening step. By operating, it is possible to prevent grinding scraps generated in the flattening step and scattering of the grinding water supplied to the grinding area to the laser irradiation means 8 and rotate the turntable 18 after performing the flattening step. In this case, the ingot 150 that has been subjected to the flattening step can be cleaned by the cleaning means 50.

  Further, in the illustrated embodiment, each of the four chuck tables 20 constituting the holding means 4 is disposed on the turntable 18, and the four chuck tables 20 are at least flattened by the rotation of the turntable 18. 6. Since it is positioned below each of the laser irradiation means 8 and the wafer peeling means 10, different steps (at least a flattening step, a peeling layer forming step, a wafer peeling step) can be performed simultaneously on a plurality of ingots. A plurality of steps can be efficiently performed.

  In the illustrated embodiment, the condensing point FP is moved relative to the ingot 2 in the direction orthogonal to the direction A in which the off angle α is formed in the release layer forming step, and the off angle α is used in index feeding. Although the example which moves the condensing point FP relatively with respect to the ingot 2 was demonstrated to the direction A in which is formed, the relative moving direction of the condensing point FP with respect to the ingot 2 is the direction in which the off angle α is formed. The direction may not be perpendicular to A, and the relative movement direction of the condensing point FP with respect to the ingot 2 in index feeding may not be the direction A in which the off angle α is formed. Further, a wafer grinding means for grinding the peeling surface of the wafer 172 peeled from the ingot 150 by the wafer peeling means 10 may be provided.

2: Wafer generator 4: Holding means 6: Flattening means 8: Laser irradiation means 10: Wafer peeling means 12: Wafer accommodating means 18: Turntable P1: Standby position P2: Flattening position P3: Release layer forming position P4: Wafer peeling position 50: Cleaning means 132: Ingot accommodating means 134: Ingot conveying means 150: Ingot 150a: First ingot 150b: Second ingot 150c: Third ingot 150d: Fourth ingot 170: Peeling layer 172: Wafer LB: Pulsed laser beam FP: Focusing point

Claims (4)

A wafer generating device for generating a wafer from an ingot,
Corresponding to the holding means for holding the ingot, the flattening means for grinding and flattening the upper surface of the ingot held by the holding means, and the thickness of the wafer to be generated from the upper surface of the ingot held by the holding means A laser irradiation means that forms a release layer by irradiating the ingot with a laser beam at a focal point of a laser beam having a wavelength that is transparent to the ingot at a depth, and peeling the wafer from the release layer while holding the upper surface of the ingot A wafer peeling means, a wafer accommodating means for accommodating the peeled wafer,
A wafer generating device composed of at least.   The wafer generating apparatus according to claim 1, further comprising: an ingot accommodating unit that accommodates the ingot; and an ingot conveying unit that conveys the ingot from the ingot accommodating unit to the holding unit.   2. The wafer generating apparatus according to claim 1, further comprising a cleaning unit that cleans the ingot flattened by the flattening unit.   2. The wafer generating apparatus according to claim 1, wherein the holding means is disposed on a turntable, and the holding means is positioned on at least the flattening means, the laser irradiation means, and the wafer peeling means by rotation of the turntable. .